Generally, a life jacket is used for preventing a person wearing the life jacket from being drowned when the person is fallen into water, wherein a space part is provided between an inner skin and an outer skin, into which air or floater is embedded to help the person who is fallen into water to be floated. The life jacket is worn essentially for preventing a drowning accident during leisure time being spent at a water side of a river, a lake or sea.
However, the life jacket is not sufficient for safeguarding a person's life with only floating function in the case where a survivor in a marine accident is unconscious or several hours to several days have been already lapsed for rescuing a survivor. That is, the main cause of death of a person who has been fallen into water for a long period of time is mostly due to hypothermia, i.e., a decline of his/her body temperature.
Accordingly, recently a technology for providing a more excellent life jacket in consideration of the above described-drawbacks has been disclosed in Korean Utility Model Registration No. 0432410 (hereinafter, referred to as “prior art”). A life jacket according to the prior art is configured such that a heating unit for generating heat through a chemical reaction is included on a space part at an inside of an outer skin thereof together with a floater. Accordingly, a rapid decline of a body temperature can be prevented by operating the heating unit by a survivor who is fallen into water.
However, in a case of the heating unit to be applied to the life jacket according to the prior art, it is configured in such a manner that an metal plate to be impacted is embedded to an inside of a vinyl pack and at the same time the vinyl pack is filled with acetic acid sodium in a liquid state and sealed to produce an exothermic reaction with impact from the metal plate. However, in the life jacket according to the prior art, there arises a problem that an unexpected external impact is transmitted to the life jacket to cause an unexpected exothermic reaction by the heating unit arranged therein while a person does activities while wearing the life jacket in advance before he/she is fallen into water. Further, in the case of the heating unit using the metal plate and acetic acid sodium, there arises a problem that the heating temperature cannot be kept for a long period of time since the exothermic reaction proceeds rapidly.